PCI: imx6: Add speed change timeout message

Currently, the timeout is never detected as count has a value of -1 if a
timeout happens, but the code is checking for 0.  Also, this patch removes
the unneeded final wait if a timeout occurs.

[bhelgaas: reworked starting from http://lkml.kernel.org/r/1433543864-7252-1-git-send-email-troy.kisky@boundarydevices.com]
Signed-off-by: Troy Kisky <troy.kisky@boundarydevices.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>

drivers/pci/host/pci-imx6.c

@@ -352,6 +352,23 @@ static int imx6_pcie_wait_for_link(struct pcie_port *pp)
 	return 0;
 }
 
+static int imx6_pcie_wait_for_speed_change(struct pcie_port *pp)
+{
+	uint32_t tmp;
+	unsigned int retries;
+
+	for (retries = 0; retries < 200; retries++) {
+		tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
+		/* Test if the speed change finished. */
+		if (!(tmp & PORT_LOGIC_SPEED_CHANGE))
+			return 0;
+		usleep_range(100, 1000);
+	}
+
+	dev_err(pp->dev, "Speed change timeout\n");
+	return -EINVAL;
+}
+
 static irqreturn_t imx6_pcie_msi_handler(int irq, void *arg)
 {
 	struct pcie_port *pp = arg;
@@ -363,7 +380,7 @@ static int imx6_pcie_start_link(struct pcie_port *pp)
 {
 	struct imx6_pcie *imx6_pcie = to_imx6_pcie(pp);
 	uint32_t tmp;
-	int ret, count;
+	int ret;
 
 	/*
 	 * Force Gen1 operation when starting the link.  In case the link is
@@ -397,29 +414,22 @@ static int imx6_pcie_start_link(struct pcie_port *pp)
 	tmp |= PORT_LOGIC_SPEED_CHANGE;
 	writel(tmp, pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
 
-	count = 200;
-	while (count--) {
-		tmp = readl(pp->dbi_base + PCIE_LINK_WIDTH_SPEED_CONTROL);
-		/* Test if the speed change finished. */
-		if (!(tmp & PORT_LOGIC_SPEED_CHANGE))
-			break;
-		usleep_range(100, 1000);
+	ret = imx6_pcie_wait_for_speed_change(pp);
+	if (ret) {
+		dev_err(pp->dev, "Failed to bring link up!\n");
+		return ret;
 	}
 
 	/* Make sure link training is finished as well! */
-	if (count)
 	ret = imx6_pcie_wait_for_link(pp);
-	else
-		ret = -EINVAL;
-
 	if (ret) {
 		dev_err(pp->dev, "Failed to bring link up!\n");
-	} else {
-		tmp = readl(pp->dbi_base + 0x80);
-		dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf);
+		return ret;
 	}
 
-	return ret;
+	tmp = readl(pp->dbi_base + 0x80);
+	dev_dbg(pp->dev, "Link up, Gen=%i\n", (tmp >> 16) & 0xf);
+	return 0;
 }
 
 static void imx6_pcie_host_init(struct pcie_port *pp)